Pipe connector

ABSTRACT

A connector for connecting pipes and for use with power tongs have a die length. The connector includes a body with threaded connection portions at each end of the body on an inside surface of the body. The connector includes a gripping surface defined on an outside surface of the body between the threaded connection portions. The gripping surface is at least as long as the die length. The connector includes a reinforced portion of the body proximate each of the threaded connection portions for increasing resistance to deformation of the body upon being connected with a pipe. The gripping surface and the reinforced portion together facilitate an increase in connection torque of pipes connected with the connector.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 15/014,941, filed Feb. 3, 2016, which claims the benefit of priorityof U.S. Provisional Patent Application No. 62/111,345, filed Feb. 3,2015.

FIELD

The present disclosure relates generally to connecting sections of pipeusing power tongs.

BACKGROUND

Underground reservoirs of fluids (e.g. hydrocarbons, water, etc.) areoften recovered by drilling a well into the reservoir and pumping fluidsout of the reservoir through tubing. A tubing string used to recoverfluids from a reservoir may be assembled from individual joints oftubing. The joints are often threaded with pin ends on both ends andconnected by connectors, which have threaded box ends on both ends.Joints of tubing string may be connected with each other by use ofconnectors. Power tongs are often used to connect the joints of tubingto each other through the connectors.

In addition to tubing, casing, liners, and other pipes used inproduction of fluids from wells are often assembled with connectorsusing power tongs.

SUMMARY

Herein disclosed is an extended pipe connector for use with power tongsand a method of making up connections using the extended connector. Theextended connector includes an extended gripping portion betweeninterference fit threaded connection portions of the connector. Theextended gripping portion facilitates gripping the extended connectorwith power tongs to make up or break a connection between pipes. Agripping surface extends along the outside surface of the extendedgripping portion along a portion of the extended connector which is freeof threading on the inside diameter of the extended connector. Theextended gripping portion is at least as long as a die which is likelyto be used on the power tongs when making or breaking connectionsbetween the connector and sections of pipe. The power tongs tong on tothe extended connector on the gripping surface, and gripping force onthe extended connector required for applying makeup torque is localizedto the extended gripping portion, avoiding direct application of forceto portions of the body with threading on the inside surface andlowering the likelihood of thread damage at a given torque valuecompared with tonging onto the outside diameter of a box endinterference fit threaded connection portion. The extended connector hasa wall thickness along at least a portion of the length of the extendedgripping portion sufficient to provide a reinforced portion of theextended connector. The reinforced portion provides resistance todeformation in the extended connector. An increase the torque requiredto thread the connector, allowing connections to be made up at greatertorque values for the same number of turns, was observed in an exampleapplication of the extended connector. This increase in torque to turnration may be due to the resistance to deformation provided by thereinforced portion. The reinforced portion may include a torque stop forfacilitating torqueing the connections to full makeup.

The extended connector facilitates making up a connection between tubingjoints or other sections of pipe without requiring that the threadedconnection portions have any particular interference fit thread pattern.The threaded connection portions may have interference fit threadingwhich matches commonly-used American Petroleum Institute (“API”)standard interference fit threading (e.g. 8 round threading used onproduction tubing, etc.), allowing connections between sections of pipewith the threading pattern to be made up using the extended connector atgreater torque values than would be the case with previous API tubingconnectors. Using an extended connector with API interference fitthreading may facilitate making up connections at torque values abovethe optimum API specification value, and in some cases at or in excessof the API maximum specification for the pipe outside diameter and steelgrade being used, with a reduced chance of thread damage. The extendedgripping surface provides an effective location to grip with powertongs. The length of the extended gripping surface also facilitatesincluding the reinforced portion between the threaded connectionportions by spreading the additional mass along the length, providingthe reinforced portion while mitigating encroachment of the connectorbody walls into a flow path through the body of the extended connector.The length of the extended gripping surface increases the contributionto increased mass of a given wall thickness of the body along thereinforced portion.

In a first aspect, the present disclosure provides a connector forconnecting pipes and for use with power tongs have a die length. Theconnector includes a body with threaded connection portions at each endof the body on an inside surface of the body. The connector includes agripping surface defined on an outside surface of the body between thethreaded connection portions. The gripping surface is at least as longas the die length. The connector includes a reinforced portion of thebody proximate each of the threaded connection portions for increasingresistance to deformation of the body upon being connected with a pipe.The gripping surface and the reinforced portion together facilitate anincrease in connection torque of pipes connected with the connector.

In a further aspect, the present disclosure provides a connector forconnecting a first pipe with a second pipe using power tongs having adie length, the connector including: an elongate body extending betweena first end and a second end; a first connection portion on an insidesurface of the body proximate the first end having interference fitthreading for connecting with the first pipe; a second connectionportion on the inside surface proximate the second end havinginterference fit threading for connecting with the second pipe; agripping surface extending along an outside surface of the elongate bodyintermediate the first connection portion and the second connectionportion for a gripping length at least as long as the die length; and areinforced portion of the elongate body intermediate the firstconnection portion and the second connection portion for resistingdeformation of the elongate body when a connection is made up with theconnector.

In some embodiments, the reinforced portion includes: a first torquestop defined on the inside surface proximate the first connectionportion for abutting the first pipe when the first pipe is made up inthe first connection portion; and a second torque stop defined on theinside surface proximate the second connection portion for abutting thesecond pipe when the second pipe is made up in the second connectionportion. In some embodiments, the reinforced portion further includes areinforcing member extending axially between the first torque stop andthe second torque stop. In some embodiments, the inside diameter of theelongate body is substantially constant along the reinforcing memberbetween the first torque stop and the second torque stop; in someembodiments, the reinforcing member extends axially along the bodysubstantially along the entire length of the gripping surface.

In some embodiments, the gripping surface includes a recessed grippingsurface; the body has a first outside diameter along the first andsecond connection portions and a second outside diameter along therecessed gripping surface; and the first outside diameter being largerthan the second outside diameter. In some embodiments, a firsttransition point between the first outside diameter and the secondoutside diameter is located intermediate the first end and the recessedgripping surface; and a second transition point between the firstoutside diameter and the second outside diameter is located intermediatethe second end and the recessed gripping surface; in some embodiments, afirst transition point between the first outside diameter and the secondoutside diameter is located intermediate the first connection portionand the second connection portion; and a second transition point betweenthe first outside diameter and the second outside diameter is locatedintermediate the first transition point and the second connectionportion.

In some embodiments, the gripping length is about 3.25″; the connectorhas an outside diameter of about 4.5″ at each of the connectionportions; and the first pipe and the second pipe each include a 3.5″outside diameter API interference fit threaded production tubing joint.In some embodiments, the body is manufactured from J-55 grade steel. Insome embodiments, the reinforced portion includes a portion of theelongate body with wall thickness of about 0.625 inches.

In some embodiments, the gripping length is about two inches longer thanthe die length.

In some embodiments, the gripping length is about twice as long as thedie length.

In some embodiments, the first pipe and the second pipe each include aproduction tubing joint, a section of well casing, or a section of wellliner.

In some embodiments, the first pipe and the second pipe each have anoutside diameter of 2.375, 2.875, 3.5, 4.5, 5.5, 7.0, 8.75, 9.625, or13.375 inches.

In a further aspect, the present disclosure provides a connector forconnecting a first pipe with a second pipe using power tongs having adie length, the connector including: an elongate body extending betweena first end and a second end; a first connection portion with APIinterference fit threading on an inside surface of the body proximatethe first end for connecting with the first pipe; a second connectionportion with API interference fit threading on the inside surfaceproximate the second end for connecting with a second pipe; a recessedgripping surface defined on an outside surface of the elongate bodyintermediate the first connection portion and the second connectionportion, the recessed gripping surface extending along the outsidesurface for a gripping length at least as long as the die length; and areinforced portion of the body extending along the body intermediate thefirst and second connection portions for resisting deformation of theelongate body when a connection is made up with the connector, thereinforced portion including: a first torque stop defined on the insidesurface proximate the first connection portion for abutting a first noseof the first pipe when the first pipe is made up in the first connectionportion; and a second torque stop defined on the inside surfaceproximate the second connection portion for abutting a second nose ofthe second pipe when the second pipe is made up in the second connectionportion.

In some embodiments, the first pipe and the second pipe includeproduction tubing and the API interference fit threading includes 8round threading.

In some embodiments, the first pipe and the second pipe includeproduction tubing and the API interference fit threading includes 10round threading.

In some embodiments, the gripping length is about 3.25″; the connectorhas an outside diameter of about 4.5″ at each of the connectionportions; and the first pipe and the second pipe each include a 3.5″outside diameter API interference fit threaded production tubing joint.In some embodiments, the body is manufactured from J-55 grade steel. Insome embodiments, the reinforced portion includes a portion of theelongate body with wall thickness of about 0.625″.

In a further aspect, the present disclosure provides a method ofconnecting a first pipe with a second pipe including providing aninterference fit threaded connector. The interference fit threadedconnector includes an extended gripping surface on an outside surface ofa body of the connector intermediate a pair of connection portions; anda reinforced portion of the body intermediate the pair of connectionportions for resisting deformation of the connector when a connection ismade up with the connector. The method also includes tonging on to thegripping surface and on to the first pipe with a power tong; rotatingthe connector relative to the first pipe to connect the connector to thefirst pipe at a torque value with the power tong; tonging on to thegripping surface and on to the second pipe with the power tong; androtating the second pipe relative to the connector to connect theconnector to the second pipe at the torque value with the power tong.

In some embodiments, the connector further includes a pair of torquestops proximate the connection portions, each of the torque stops forabutting a nose of a pipe threaded into the connection portion proximatethe torque stop. In some embodiments, abutting the nose is indicative ofthe torque value having been reached.

In some embodiments, the connection portions are threaded with APIinterference fit threading. In some embodiments, the torque value is inexcess of the API optimum value at the same grade of steel for aconnector used with pipe having an outside diameter equal to a referenceoutside diameter value of the first pipe and the second pipe. In someembodiments, the torque value is in excess of the API maximum value atthe same grade of steel for a connector used with pipe having an outsidediameter equal to the reference outside diameter value.

In some embodiments, the connection portions are threaded with APIinterference fit threading. In some embodiments, the gripping length isabout 3.25″; the connector has an outside diameter of about 4.5″ at eachof the connection portions; and the first pipe and the second pipe eachinclude a 3.5″ outside diameter API interference fit threaded productiontubing joint. In some embodiments, the body is manufactured from J-55grade steel. In some embodiments, the reinforced portion includes aportion of the elongate body with wall thickness of about 0.625″. Insome embodiments, the torque value is in excess of the API maximum valuefor a connector used with pipe having an outside diameter equal to thereference outside diameter value. In some embodiments, the torque valueis at least 3,000 ft·lbs. In some embodiments, the torque value is atleast 3,600 ft·lbs.

In some embodiments, the first pipe and the second pipe are productiontubing joints, sections of well casing, or sections of well liner.

Other aspects and features of the present disclosure will becomeapparent to those ordinarily skilled in the art upon review of thefollowing description of specific embodiments in conjunction with theaccompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure will now be described, by way ofexample only, with reference to the attached figures, in which featuressharing reference numerals with a common final two digits of a referencenumeral correspond to similar features across multiple figures (e.g. thebody 12, 112, 212, 312, etc.).

FIG. 1 is a previous well tubing connector connected with a singletubing joint;

FIG. 2 is the previous well tubing connector of FIG. 1 being connectedwith a pair of tubing joints using a pair of power tongs;

FIG. 3 is a well tubing connector as described herein;

FIG. 4 is the well tubing connector of FIG. 3 being connected with atubing joint using a pair of power tongs;

FIG. 5 is a well tubing connector as described herein;

FIG. 6 is the well tubing connector of FIG. 5 being connected with apair of tubing joints using a pair of power tongs;

FIG. 7 is a well tubing connector as described herein;

FIG. 8 is a well tubing connector as described herein;

FIG. 9 is a plot of applied torque as a function of the number of turnsfor previous connectors and connectors as described herein torqued todifferent values;

FIG. 10 is a plot of applied torque as a function of the number of turnsfor an extended connector as described herein gripped at an extendedgripping surface and torqued to different values;

FIG. 11 is a plot of applied torque as a function of the number of turnsfor an extended connector as described herein gripped at a box end andtorqued to different values; and

FIG. 12 is a plot of applied torque as a function of the number of turnsfor a standard API collar gripped at and torqued to different values.

DETAILED DESCRIPTION

Generally, the present disclosure provides connectors for connectingsections of pipe used in production of fluids (e.g. production tubingjoints, casing sections, liner sections, etc.). The connectors have anelongate body including an extended tong gripping portion intermediateinterference fit threaded connection portions at either end of the body.The outside surface of the tong gripping portion provides a tonggripping surface to facilitate gripping the connectors with power tongs.The length of the tong gripping portion for a given connector isselected with reference to the outside diameter of the pipes with whichthe given connector will be used and the length of power tong dies whichwould be used on power tongs gripping the connector. The length of thetong gripping portion is at least as long as the expected die length.The expected die length may be a maximum die length for power tongsbeing used with the connector and with pipe of the outside diameter forwhich the well tubing connector is designed to be used.

The extended connectors disclosed herein include a reinforced portion ofthe body intermediate the two threaded connection portions. Thereinforced portion, which may include a torque stop or other radialextension into a flow passage defined within the connector, increasesthe strength and resistance to deformation of the body proximate thethreaded connection portions and in some cases at the threadedconnections. The torque required per turn to thread a pin end into oneof the two threaded connection portions is increased relative toprevious connectors having the same thread. The increase in torque perturn facilitates connection of pipes having commonly-used threadpatterns at greater torque than with previous connectors. The length ofthe tong gripping portion facilitates providing the reinforced portionwithout increasing a wall thickness of the connector body to the pointwhere the flow passage lacks a sufficient cross-section area for aselected fluid flow rate. The reinforced portion may be dimensioned suchthat the flow passage remains at least as wide as the flow passagewithin the pipe to be connected with the extended connector. Thereinforced portion may include a torque stop for facilitating torqueingthe connections to full makeup. When the connections are completely madeup, a recognizable increase in torque with no further turning results,mitigating unintentional or overthreading of the extended connectorbeyond full makeup.

The increase in torque which the connector may be made up at as a resultof the extended gripping surface and the reinforced portion is notdependent on any particular threading pattern and the threaded connectorends may be threaded with a standard American Petroleum Institute(“API”) interference fit thread. API interference fit threading onproduction tubing with an outside diameter of 2.375″, 2.875″, 3.5″, or4.5″ commonly includes API standard 8 round EUE interference fit threador API standard 10 round NU interference fit thread. Greater diametersof production tubing and of casing or liner such as 5.5″, 7.0″, 8.75″,9.625″, or 13.375″ may also include interference fit thread. Theconnectors described herein may facilitate making up connections athigher torque values relative to previous connectors using the same APIinterference fit threading for a given outside diameter of pipe and witha given grade of steel (e.g. J-55, N-80, P-120, etc.).

Increasing the torque value at which a connection is made up requiresgripping the connection with greater force to prevent slipping in thetong dies. Increasing the force on a box-end connector, as would be thecase in a standard API threaded connector, means increasing the grippingforce on the same portion of the connector that is engaging the tubingthreading while a connection is made up or broken. As a result, anincrease in connection torque, and the corresponding increase ingripping force required to prevent slipping, may result in acorresponding increase in likelihood of thread damage when gripping on abox end of the connector. With the extended connector, any increase inthe gripping force on the extended connector is localized to theextended gripping portion and does not affect the connection portion. Asa result, it may be possible to make up a connection with the extendedconnector at a greater torque without thread damage than with a standardlength API connector. The localization of force of the extended grippingportion, along with the additional strength and torque per turn ratioprovided by the reinforced portion, facilitate making up a connectionbetween two pipes having interference fit threading compatible with theextended connector at a greater torque value than with previousconnectors, while reducing the chances of thread damage.

Connectors for threaded tubing joins can be connected at a given levelof torque. For example, previous connectors for 3.5″ API interferencefit threaded tubing joints made from J-55 grade steel with 8 round EUEinterference fit threading can be connected at between about 1,710 andabout 2,850 ft·lbs according to API specification, with an optimalconnection torque of about 2,280 ft·lbs. An extended connector for thesame 3.5″ API EUE 8 round tubing joints made from J-55 grade steel maybe torqued to between about 3,000 ft·lbs and about 3,600 ft·lbs.

Previous Connectors

FIG. 1 shows a previous tubing joint connector P01 in cross section witha first tubing joint 40 threaded into the previous tubing jointconnector P01. As shown, substantially the entire length of the previoustubing joint connector P01 has an inside diameter covered in threadingto threadedly receive pin ends of tubing joints. When using a power tongon the previous connector P01, it would be necessary to tong on to anoutside diameter of the previous tubing connector P01 along a portion ofthe previous tubing connector P01 including threading on an insidediameter.

FIG. 2 shows a pair of power tongs 50 being used to connect the firsttubing joint 40 with a second tubing joint 42 using the previous tubingjoint connector P01. The first tubing joint 40 is connected with a millside P02 of the previous tubing joint connector P01. The second tubingjoint 42 is connected with a field side P04 of the previous tubing jointconnector P01. The power tongs 50 include a powered tong 52 and a backuptong 54. The powered tong 52 includes a powered tong die 56 which gripsa body being rotated, in this case the second tubing joint 42. Thebackup tong includes a backup tong die 58 which grips a body being heldstationary relative to the body being rotated, in this case the previoustubing connector P01.

The powered tong 52 is used to rotate the second tubing joint 42relative to the previous tubing joint connector P01. The backup tong 54holds the previous tubing joint connector P01 and the first tubing joint40 stationary relative to the second tubing joint 42. The powered tong52 grips on the outside diameter of the second tubing joint 42. Thebackup tong 54 grips on the outside diameter of the previous tubingjoint connector P01. Different examples of power tongs may include abackup tong which extends around all or only a portion of the outsidediameter of a previous tubing joint connector P01.

When the power tongs 50 are used to make up a connection between theprevious tubing joint connector P01 and the second tubing joint 42, thebackup tong 54 often grips the mill side P02 of the previous tubingjoint connector P01 at a portion of the previous tubing joint connectorP01 within which a first threaded pin end 44 of the first tubing joint40 is connected.

Extended Connector

FIG. 3 shows an extended connector 10 having a body 12 extending betweena first end 14 and a second end 16. The inside diameter of the body 12includes a first interference fit threaded connection portion 15extending from the first end 14 and a second interference fit threadedconnection portion 17 extending from the second end 16. The threadedconnection portions 15, 17 are for connecting with interference fitthreaded pin portions on each end of tubing joints and have sufficientaxial depth to connect to the interference fit threaded pin ends of atubing joint (see FIG. 4). The body 12 includes a tong gripping portion20 on an outside surface of the body 12 between the first threadedportion 15 and the second threaded connection portion 17. The body 12includes a reinforced portion 30 extending between the first threadedconnection portion 15 and the second threaded connection portion 17.

The tong gripping portion 20 extends along the outside surface of thebody 12 along a portion of the body 12 where neither of the threadedconnection portions 15 or 17 are located on an inside surface 18 of thebody 12. A first transition point 28 separates the tong gripping portion20 from the first threaded connection portion 15. A second transitionpoint 29 separates the tong gripping portion 20 from the second threadedconnection portion 17. A tong gripping surface 26 is defined on theoutside surface of the body 12 along the tong gripping portion 20. Thetransition points 28, 29 each define a boundary between one of thethreaded connection portions 15, 17, respectively, and the tong grippingportion 20. The tong gripping portion 20 may be gripped by the powertongs 50 with less risk of damage to the extended connector 10 than ifeither of the threaded connection portions 15, 17 is gripped,particularly where the threaded connections portions 15, 17 beinggripped is connected with a threaded pin portion of a tubing joint.

The tong gripping portion 20 is at least as long as dies used on powertongs which will be used to rotate the extended connector 10 or welltubing with which it will be used. The die lengths are selected withreference to the outside diameter of the extended connector 10 and ofwell tubing with which it will be used, the torque required to make upthe connection, and the application of the well tubing, and so thelength of the tong gripping portion 20 is also indirectly selected withreference to these factors. For example, on power tongs 50 usable withpipes having outside diameters of between about 3.5″ and about 5.5″,backup tong dies 58 may have a die length of about 1.5″ and powered tongdies 56 may have a die length of about 3.0″. The gripping portion 20would be at least 3.0″ for use with such power tongs 50, and may beabout 5″, allowing a one-inch margin on each side of a power tong die 56or 58 located at the center of the gripping portion 20. Where theextended connector 10 is designed for use on larger outside diametertubing, or on liner or casing (e.g. 7″, 8.75″, 9.625″, 13.375″, etc.),the gripping portion 20 would be larger to accommodate the larger diesizes on power tongs 50 which would be used on such higher-outsidediameter tubing, casing, or other pipes.

The reinforced portion 30 extends along on the inside surface 18 of thebody 12 intermediate the threaded connection portions 15, 17. Thereinforced portion 30 extends axially between approximately the firsttransition point 28 and the second transition point 29. The reinforcedportion 30 ends with a first torque stop 32 proximate the firsttransition point 28 and with a second torque stop 34 proximate thesecond transition point 29. The reinforced portion 30 extends along areinforced length 36 of the body 12. The body 12 has a wall thickness 38along the reinforced length 36. The wall thickness 38 is selected toprovide strength and resistance to deformation to the body 12. Withoutbeing bound by any theory, an increased torque to turn ratio ofconnections with the threaded connection portions 15, 17 relative tothat observed in previous connectors may be provided by the reinforcedportion 30. By providing some level of control over the makeup torqueand the torque to turn ratio of the threaded connection portions 15, 17without changing the thread pattern, including the reinforced portionfacilitates using the extended connector 10 to connect sections of pipewith commonly used thread patters to be made up at a greater torque thanwith previous connectors.

Increasing the length 36 of the reinforced portion 30, increasing thewall thickness 38 of the body 12 along the reinforced portion 30, ormanufacturing the body 12 from a stronger grade of steel, will eachincrease the strength and resistance to deforming of the body 12. Theseincreases in strength and resistance to deforming in turn facilitateconnecting the tubing joints 40, 42 with the extended connector 10 at ahigher torque value for the same number of turns while reducing thechances of galling or other failure of the tubing joints 40, 42 or theextended connector 10. The gripping surface 20 provides a low-risklocation on the body 12 for applying the greater gripping forcesrequired to apply the higher torque values enabled by the reinforcedportion 30.

A connector may also include a reinforced portion extending along alesser extent of the inside surface 18 between the threaded connectionportions 15, 17. In this case the reinforced portion would still beengineered to contribute sufficient strength and resistance todeformation to the body 12 to allow connections to be made up at aparticular torque value. The reinforced portion 30 has a sufficientlength 36 such that the width 38 need not extend into a flow passagewithin the connector to such an extent as to narrow the flow passage tolower than the pipe with which the connector 10 will be used. Areinforced portion could also extend outward from the outside surface ofthe connector body 12 and provide additional strength and resistance todeforming to the body 12. However, adding a reinforced portion to theoutside surface of the connector body 12 would also increase the outsidediameter of the body 12, likely beyond API specification outsidediameter, which in many applications would be a significant drawback.

FIG. 4 shows a pair of power tongs 50 being used to connect a firsttubing joint 40 with a second tubing joint 42 using the extendedconnector 10. A first threaded pin portion 44 of the first tubing joint40 is engaged with the first threaded connection portion 15, which is ona mill side of the extended connector 10. A second threaded pin portion46 of the second tubing joint 42 is engaged with the second threadedconnection portion 17, which is on a field side of the extendedconnector 10.

The make-up point between the extended connector 10 and the first tubingjoints 40 is at the nose of the first pin end 44. Similarly, the make-uppoint between the extended connector 10 and the second tubing joints 42is at the nose of the second pin end 46. When the first tubing joint 40is connected with the extended connector 10, the pin end 44 is threadedinto the first connector end 14 and abuts the first torque stop 32 ofthe reinforced portion 30. Similarly, when the second tubing joint 42 isconnected with the extended connector 10, the pin end 46 is threadedinto the second connector end 16 and abuts the second torque stop 34 ofthe reinforced portion 30.

The power tongs 50 include a powered tong 52 and a backup tong 54. Thepowered tong 52 is used to rotate the second tubing joint 42 relative tothe extended connector 10. The powered tong 52 grips the extendedconnector 10 on the gripping portion 20. The backup tong 54 holds theextended connector 10 stationary relative to the first tubing joint 40.Where the power tongs 50 are used to break a connection between theextended connector 10 and the first tubing joint 40, the grippingportion 20 also provides a surface which may be hammered on to assist inbreaking the connection without hammering on an outside surface of aportion of the body 12 along the threaded connection portions 15, 17.

Keeping the body material and thread design constant, the grippingsurface 20 and the reinforced portion 30 together allow the tubingjoints 40, 42 to be threaded into the extended connector 10 at aselected torque value greater than with previous connectors (e.g. theconnector P01, etc.) in which threaded connector ends are proximate eachother.

The gripping portion 20, being at least as long as the longitudinallength of a die 56 or 58 which would be used on power tongs 50 of anappropriate size for the extended connector 10, is sufficiently long tobe easily gripped by the power tongs 50. When using power tongs 50 toinstall the extended connector disclosed herein, there is no need togrip on a portion of the extended connector 10 which includes thethreaded connection portions 15, 17 on the inside surface 18. Theextended gripping portion 20 provides a portion of the extendedconnector 10 which is long enough to be easily gripped by the powertongs 50 and which may be gripped and torqued with a reduced chance ofthread damage compared with gripping and torqueing the extendedconnector 10 on the outside surface of a portion which includes one ofthe threaded connection portions 15, 17 on the inside surface 18. Bymitigating potential damage to threading which could result fromtorqueing during makeup, the extended connector 10 facilitates threadingto a greater torque value than when tonging onto a box end of a standardAPI tubing connector.

The power tongs 50 tong on to the extended connector 10 on the grippingportion 20, and any increase in gripping force on the extended connectoraccompanying an increase in makeup torque is localized to the extendedgripping portion 20, avoiding application of force to threading locatedon the threaded connection portions 15, 17 and mitigating the likelihoodof thread damage at a given torque value compared with when tonging ontothe outside diameter of a box end connection portion of a connector 10.

The reinforced portion 30 of the extended connector 10 proximate thethreaded connection portions 15, 17 and the corresponding increase intorque required to engage the threads facilitates making up a connectionat a greater torque value. The extended connector 10 facilitates makingup a connection at a greater torque without thread damage, or with alowered chance of thread damage, than with a standard API connector.

Recessed Gripping Portion

FIG. 5 shows an extended connector 110 wherein a recessed tong grippingportion 122 in the body 112 is defined both by the absence of thethreaded connection portions 115, 117, and by a change in outsidediameter of the body 112. The change in outside diameter of the body 112is a result of a first taper in the profile of the body 112 at a firstoutside diameter transition point 123 and a second taper in the profileof the body 112 outside diameter at a second outside diameter transitionpoint 124 of the body 112. The first outside diameter transition point123 is at a portion of the body 112 which includes the first transitionpoint 128 on the inside surface 118. Similarly, the second outsidediameter transition point 124 is at a portion of the body 112 whichincludes the second transition point 129 on the inside surface 118.

FIG. 6 shows a pair of power tongs 150 being used to connect a firsttubing joint 140 with a second tubing joint 142 using the extendedconnector 110. The first threaded pin portion 144 of the first tubingjoint 140 is engaged with the first threaded connection portion 115,which is on a mill side of the extended connector 110. The secondthreaded pin portion 146 of the second tubing joint 142 is engaged withthe second threaded connection portion 117, which is on a field side ofthe extended connector 110. The powered tong 152 is used to rotate thesecond tubing joint 142 relative to the extended connector 110. Thebackup tong 154 holds the first tubing joint 140 and the extendedconnector 110 stationary relative to the second tubing joint 142. Thebackup tong grips the extended connector 110 on the recessed grippingportion 122. Similarly, when the power tongs 150 are used to make up aconnection between the extended connector 110 and the first tubing joint140, the backup tong 154 grips the extended connector 110 on therecessed gripping portion 122.

Where the power tongs 150 are used to break a connection between theextended connector 110 and the first tubing joint 140, the recessedgripping portion 122 also provides a surface which may be hammered on toassist in breaking the connection without hammering on an outsidesurface of a portion of the body 112 along the threaded connectionportions 115, 117.

The recessed nature of the recessed gripping portion 122 facilitateslocating and gripping the extended connector 110 on the recessedgripping portion 122 with the power tongs 150 relative to gripping onthe gripping portion 20 of the extended connector 10. The recessedgripping portion 122 provides a location for tonging onto which issimple to locate visually and which an operator can be confident is freeof threading on the inside surface 118.

The change in outside diameter at the outside diameter transition points123, 124 may be effected by the tapered portions as shown or otherwise(e.g. steps, etc.). The transition points 128, 129 each define aboundary between one of the threaded connection portions 115, 117, andthe recessed gripping portion 122. In contrast, the outside diametertransition points 123, 124 each define a boundary between differentoutside diameter values of the body 112. The outside diameter transitionpoints 123, 124 may be located at portions of the body 112 other thanthe transition points 128, 129.

FIG. 7 is an extended connector 210 in which the recessed grippingportion 222 extends into portions of the body 212 which include thethreaded connection portions 215, 217 on the inside surface 218. Thefirst outside diameter transition point 223 is located on the firstthreaded connection portion 215. The second outside diameter transitionpoint 224 is located on the first threaded connection portion 217. Thefirst outside diameter transition point 223 is between the firsttransition point 228 and the first end 214. The second outside diametertransition point 224 is between the second transition point 229 and thesecond end 216.

The recessed gripping portion 222, which is defined between the firstand second transition points 228, 229, extends along a portion of thebody 212 free of the threading of the first and second threadedconnection portions 215, 217 on the inside diameter 218, which wouldordinarily be engaged a pin end threading on a tubing joint when theextended connector 210 is included in a connection. The axial depth ofthe threaded connection portions 215, 217 and length of the recessedgripping portion 222 are selected to allow the threaded connectionportions 215, 217 to engage threaded pin portions of tubing joints, andfor power tongs to grip the recessed gripping portion 222 withoutoverlapping on the threaded connection portions 215, 217. For aconnection to be used with 3.5″ API interference fit tubing, a distancebetween each of the outside diameter transition portions 223, 224 andeach of the respective transition points 228, 229 may be about 0.375″.

FIG. 8 is a connector 310 in which the recessed gripping portion 322.The first transition point 328 is between the first outside diametertransition point 323 and the first end 314. The second transition point329 is between the second outside diameter transition point 324 and thesecond end 316. Compared with the extended connector 210, the extendedconnector 310 would be expected to have greater strength and resistanceto deformation on threading a pipe into either of the connectors 210,310.

Example Connector for 3.5″ API EUE Production Tubing

An extended connector was prepared with a similar design to the extendedconnector 210 for connection with 3.5″ API EUE interference fitproduction tubing with an 8 round thread pattern. A previous connectorfor 3.5″ API EUE tubing made from J-55 steel can be connected at betweenabout 1,710 and about 2,850 ft·lbs according to API specification, withan optimal connection torque of about 2,280 ft·lbs. The extendedconnector, also made from J-55 steel, connected the same 3.5″ API EUEtubing joints at torque values of about 3,000 ft·lbs and about 3,600ft·lbs, in both cases without thread damage.

On the extended connector, with reference to the extended connector 210,the distance between the outside diameter transition points 228, 229 was4.0″. The recessed gripping portion length 222 was 3.25″. The outsidediameter of the extended connector 210 at the first and second threadedconnection portions 215, 217 was 4.5″. The wall thickness 238 along thereinforced portion 230 was 0.625″.

TABLE 1 2,280 ft·lbs 3,000 ft·lbs 3,600 ft·lbs extended connector NotDamaged Not Not on gripping surface Damaged Damaged extended connectorNot Damaged Damaged Damaged on box end API coupling Not Damaged DamagedDamaged

Table 1 shows a matrix of connectors and torque values tested, with anindication of whether the threads of the connector, the tubing joints,or both were damaged for each set of conditions. As shown in Table 1,tightening a previous connector to torque values of about 3,000 or 3,600ft·lbs is likely to result in galling of the threads of the previousconnector, the tubing joints, or both. In addition, without being boundby any theory, gripping a previous connector with sufficient force tohold it steady while being tightened to about 3,000 or to 3,600 ft·lbsmay itself result in crushing and galling of the threads of theconnector and the tubing joints when gripping on the box end of aconnection being made up or which has been made up. Table 1 also showsthat the extended connector is less likely to be damaged by torqueing to3,000 or 3,600 ft·lbs than the previous connector when the extendedconnector is gripped on the extended gripping portion. When gripped onthe box end of one of the threaded connection portions, thread damageresulted in the tests. Again, without being bound by any theory, thismay result from the increased gripping force required to rotate theconnector at a higher torque, and an increased likelihood of damage whengripping on a box end rather than on the gripping portion.

Each of the API collar and the extended collar were also pull tested to110,000 lbs. when connected at 3,600 ft·lbs and passed the test.However, when disconnected the API collar had damaged threads as shownabove in Table 1. API specification would require that the pipe betested to 142,460 lbs., but this data remains indicative that theconnections are sufficient for some applications, including inlow-pressure wells with artificial lift.

FIG. 9 shows data of torque vs the number of turns for the data setsshown in Table 1. In FIG. 9, data of the extended connector gripping onthe gripping surface is shown in solid lines, data of the extendedconnector gripping on the box end is shown in dashed lines, and data ofthe API coupling is shown in dotted lines. This legend is maintained inFIGS. 10 to 12 which shown the datasets of individually. When theextended connector is torqued to 3,000 ft·lbs, or in a second dataset,over 3,600 ft·lbs, the first torque stop 232 is engaged and rotationstops. At 2,280 ft·lbs, the extended connector has completed less than1.5 turns. This, and the much steeper slopes of the data with theextended connector, show that more torque is required to thread a pinend into the extended connector than into an API connector. As a result,the connection is much tighter than with the API connector.

Torque vs time data was not collected for the API connector at 3,600ft·lbs. The two datasets torqued to 2,280 ft·lbs are respectively for astandard OD API connector and a shaved API connector for slimlineapplications. However, it was confirmed, as in Table 1, that torqueingto 3,600 damaged the API connector.

FIGS. 10 to 12 respectively show the data from FIG. 9 of only theextended connector on the gripping surface, the extended connector onthe box end, and the regular API connection on the box end. FIG. 9allows easy comparison of the datasets to review trends in the data.However, FIGS. 10 to 12 allow the individual data sets to be viewed moreeasily.

Possible Efficiencies

Canadian Patent No. 2,743,294 to Klotz et al. includes a description offeatures directed to facilitating use of power tongs with well tools,such as tubing hangers and tubing drains. However, Klotz et al. do notdisclose use of an extended gripping portion in a connector orapplication of the reinforced portion of the extended connector. Suchfeatures are absent from previous connectors. In addition, connectorsfor tubing or other pipe are simpler, less expensive to manufacture, andused in greater numbers than well tools such as those shown in Klotz etal., incentivizing minimizing the material used for such previousconnectors as described above. While the extended connectors describedherein require more material to manufacture than is generally the casewith pipe connectors for low-pressure wells, the extended connectors mayprovide efficiencies in terms of fewer lost manhours and fewer damagedconnectors.

When using power tongs to connect or disconnect tubing joints,connectors are often gripped by powered or backup tongs (in some casesnotwithstanding an accepted practice of tonging on to production tubingon mill and field sides of a connector instead of tonging on to theconnector). Damaged connectors and associated lost time may result fromgripping previous connectors with power tongs on an outside surface of aportion of the previous connector which includes threading on the insidesurface. When using power tongs to install previous connectors, theprevious connectors are in many cases gripped by a power tong on anoutside surface of the previous connector along a portion of theconnector which includes on its inside surface threading which is beingconnected with a joint of tubing or is already connected with a joint oftubing. The simplicity with which the extended connector may be usedwith power tongs may result in less time being lost and the lack ofgripping on a box end including threads on an inside surface may resultin fewer damaged connectors.

Applications with Progressive Cavity Pumps

Pipe connectors, particularly production tubing connectors intended foruse with low-pressure wells, are often designed to minimize the amountof material and effort that is needed to prepare the connector and yetremain functional. Such an approach to connectors would often be used inlow pressure-wells, where artificial lift, such as a progressive cavitypump (a “PCP”) may also be used. Given the large number of productiontubing connectors required for a typical oil well run with tubingjoints, there is a significant incentive to minimize the material costof each connector and manufacture connectors with as little material aspossible.

During production through a tubing string including a PCP, a PCP rotormay cause rotation of the production string by transferring torque. Suchrotation of the production string may loosen connection between theconnectors and tubing, resulting in dropping the production string intothe well. Where a production string is dropped, costly servicing isrequired. This problem has been previously addressed by use of a torqueanchor, which prevents transfer of the PCP rotor torque to theproduction string. Torque anchors are connected to the production stringat or proximate the downhole portion and include anchor blocks orsimilar features which engage with the inside surface of casing or thewell bore when the torque anchor is actuated, preventing rotation of theproduction string as a result of transfer of PCP rotor torque to theproduction string. In some cases, torque anchors may puncture orotherwise damage the inside surface of well casing.

With 3,600 ft·lbs of torque applied to connections between productiontubing joints, torque transfer from a PCP rotor is far less likely toresult in unscrewing of the production string and the need for a torqueanchor when using a PCP in the production string is mitigated when usingthe extended connector and connecting at 3,000 or 3,600 ft·lbs. Thegreater torque facilitated by the extended gripping portion and thereinforced portion mitigate backing off when using a PCP to produce froma low-pressure oil well.

In contrast, with previous API standard interference fit connectors,connections between the previous connector and the tubing joints aretypically made at about 2,280 ft·lbs, and transfer of torque from a PCProtor to a tubing string connected at this torque may result inunscrewing of connections and dropping of the production string.

The torque expected to be generated by a PCP may be estimated based onthe drive rod size and grade. The smaller 1″ drive rods are typicallyused with low flowrate, low lift PCPs and can't handle a lot of torque.These smaller rods likely cannot put out sufficient torque to back off a3.5″ API EUE interference fit thread connections torqued to the optimumspecification of 2,280 ft·lbs. Rods with a diameter of 1.25″ or 1.5″have torsional strengths in the range where the such couplings couldpotentially back off and the extended coupling may provide an advantagein mitigating backing off.

Flowrate in a PCP is directly proportional to RPM for any given size ofPCP or PDM. Torque is linearly related to pressure drop across themotor. The pressure drop in a PCP is created because of the fluidviscosity, flowrate, lifting height, tubing size, and other variables.These variables are known or can be estimated when designing thecompletion and sizing the PCP.

If the PCP selected for use is expected to generate higher torque thanstandard API interference fit pipe connections, a tubing anchor will beused. However, backoff can occur even if expected PCP torque is lowerthan connection torque because of vibration and the possibility ofconnection(s) not being properly torqued to spec. As a result,increasing the torque in the connections will reduce the risk of backoffespecially when using high flowrate, higher lift PCPs.

In summary, each PCP is selected on the basis of the expected flowrate,required lift, fluid viscosity and other well related parameters. Thetorque generated during operation will depend on the specifics of thePCP. High flowrate, high lift PCPs can generate very large torque valuesthat are well in excess of the typical pipe connection torque. With lowflowrate, low lift PCPs, the torque may not be high at all, even withheavy viscous oil. Candidates where higher torque connections with theextended connector is quantifiably beneficial would be easy to identifybased on knowledge of the specifications of the PCP that has beenselected for the well. In other cases, the extended connector may beless clearly required but provide additional assurance that backing offwill be mitigated.

Examples Only

In the preceding description, for purposes of explanation, numerousdetails are set forth in order to provide a thorough understanding ofthe embodiments. However, it will be apparent to one skilled in the artthat these specific details are not required.

The above-described embodiments are intended to be examples only.

Alterations, modifications and variations can be effected to theparticular embodiments by those of skill in the art without departingfrom the scope, which is defined solely by the claims appended hereto.

What is claimed is:
 1. A connector for connecting a first pipe with asecond pipe using power tongs having a die length, the connectorcomprising: an elongate body extending between a first end and a secondend; a first connection portion on an inside surface of the bodyproximate the first end having interference fit threading for connectingwith the first pipe; a second connection portion on the inside surfaceproximate the second end having interference fit threading forconnecting with the second pipe; a gripping surface extending along anoutside surface of the body intermediate the first connection portionand the second connection portion for a gripping length at least as longas the die length; and a reinforced portion of the body intermediate thefirst connection portion and the second connection portion for resistingdeformation of the body when a connection is made up with the connector.2. The connector of claim 1 wherein the reinforced portion comprises: afirst torque stop defined on the inside surface proximate the firstconnection portion for abutting the first pipe when the first pipe ismade up in the first connection portion; and a second torque stopdefined on the inside surface proximate the second connection portionfor abutting the second pipe when the second pipe is made up in thesecond connection portion.
 3. The connector of claim 2 wherein thereinforced portion further comprises a reinforcing member extendingaxially between the first torque stop and the second torque stop.
 4. Theconnector of claim 3 wherein the inside diameter of the body issubstantially constant along the reinforcing member between the firsttorque stop and the second torque stop.
 5. The connector of claim 3wherein the reinforcing member extends axially along the bodysubstantially along the entire length of the gripping surface.
 6. Theconnector of claim 1 wherein: the gripping surface comprises a recessedgripping surface; the body has a first outside diameter along the firstand second connection portions and a second outside diameter along therecessed gripping surface; and the first outside diameter being largerthan the second outside diameter.
 7. The connector of claim 6 wherein: afirst transition point between the first outside diameter and the secondoutside diameter is located intermediate the first end and the recessedgripping surface; and a second transition point between the firstoutside diameter and the second outside diameter is located intermediatethe second end and the recessed gripping surface.
 8. The connector ofclaim 6 wherein: a first transition point between the first outsidediameter and the second outside diameter is located intermediate thefirst connection portion and the second connection portion; and a secondtransition point between the first outside diameter and the secondoutside diameter is located intermediate the first transition point andthe second connection portion.
 9. The connector of claim 1 wherein: thegripping length is about 3.25″; the connector has an outside diameter ofabout 4.5″ at each of the connection portions; and the first pipe andthe second pipe each comprise a 3.5″ outside diameter API interferencefit threaded production tubing joint.
 10. The connector of claim 9wherein the body is manufactured from J-55 grade steel.
 11. Theconnector of claim 10 wherein the reinforced portion comprises a portionof the body with wall thickness of about 0.625 inches.
 12. The connectorof claim 1 wherein the gripping length is about two inches longer thanthe die length.
 13. The connector of claim 1 wherein the gripping lengthis about twice as long as the die length.
 14. The connector of claim 1wherein the first pipe and the second pipe each comprise a productiontubing joint.
 15. The connector of claim 1 wherein the first pipe andthe second pipe each have an outside diameter of 3.5 inches.
 16. Aconnector for connecting a first pipe with a second pipe using powertongs having a die length, the connector comprising: an elongate bodyextending between a first end and a second end; a first connectionportion with API interference fit threading on an inside surface of thebody proximate the first end for connecting with the first pipe; asecond connection portion with API interference fit threading on theinside surface proximate the second end for connecting with a secondpipe; a recessed gripping surface defined on an outside surface of thebody intermediate the first connection portion and the second connectionportion, the recessed gripping surface extending along the outsidesurface for a gripping length at least as long as the die length; and areinforced portion of the body extending along the body intermediate thefirst and second connection portions for resisting deformation of thebody when a connection is made up with the connector, the reinforcedportion comprising: a first torque stop defined on the inside surfaceproximate the first connection portion for abutting a first nose of thefirst pipe when the first pipe is made up in the first connectionportion; and a second torque stop defined on the inside surfaceproximate the second connection portion for abutting a second nose ofthe second pipe when the second pipe is made up in the second connectionportion.
 17. The connector of claim 16 wherein the first pipe and thesecond pipe comprise production tubing and the API interference fitthreading comprises 8 round threading.
 18. The connector of claim 16wherein the first pipe and the second pipe comprise production tubingand the API interference fit threading comprises 10 round threading. 19.The connector of claim 16 wherein the gripping length is about 3.25″;the connector has an outside diameter of about 4.5″ at each of theconnection portions; and the first pipe and the second pipe eachcomprise a 3.5″ outside diameter API interference fit threadedproduction tubing joint.
 20. The connector of claim 19 wherein the bodyis manufactured from J-55 grade steel.
 21. The connector of claim 20wherein the reinforced portion comprises a portion of the body with wallthickness of about 0.625″.
 22. A method of connecting a first pipe witha second pipe comprising: providing an interference fit threadedconnector comprising: an extended gripping surface on an outside surfaceof a body of the connector intermediate a pair of connection portions;and a reinforced portion of the body intermediate the pair of connectionportions for resisting deformation of the connector when a connection ismade up with the connector; tonging on to the gripping surface and on tothe first pipe with a power tong; rotating the connector relative to thefirst pipe to connect the connector to the first pipe at a torque valuewith the power tong; tonging on to the gripping surface and on to thesecond pipe with the power tong; and rotating the second pipe relativeto the connector to connect the connector to the second pipe at thetorque value with the power tong.